Secondary prevention of myocardial infarction in people with dementia: a multi-jurisdictional retrospective cohort study in Asia, Europe and the USA.

Abstract

Background: Statins, renin-angiotensin system inhibitors (RASIs) and beta-blockers are guideline-recommended cardiovascular medications post-myocardial infarction (MI) for secondary prevention, but evidence for people with dementia is scarce.

Objective: To evaluate the association between post-MI cardiovascular medication use and the risk of cardiovascular outcomes and mortality, focusing on people with dementia.

Design: Large retrospective cohort study using data from Australia, Finland, Taiwan, the UK and the USA.

Subjects: People with and without dementia.

Methods: Seven exposure groups were assigned using one or combinations of the three guideline-recommended medication classes-(i) statin, RASI and beta-blocker, (ii) statin and beta-blocker, (iii) statin and RASI, (iv) RASI and beta-blocker, (v) statin only, (vi) beta-blocker only and (vii) RASI only, based on medication records during a 60-day landmark period post-MI. Recurrent MI, major adverse cardiovascular event (MACE) and all-cause mortality were evaluated as outcomes. Jurisdiction-specific results were pooled together using meta-analyses.

Results: A total of 28 122 people with dementia and 260 360 people without dementia were included. Among people with dementia, using any single or two medications carried a similar risk of recurrent MI and MACE as using all three guideline-recommended medications, except that using RASI and a beta-blocker without a statin was associated with a lower risk of recurrent MI (HR 0.85; 95% CI, 0.75-0.96). Using a statin and RASI without beta-blockers resulted in similar all-cause mortality to using all three (HR 1.16; 95% CI, 0.97-1.39), while all the remaining single- or dual-medication regimens were associated with higher risks of all-cause mortality.

Conclusions: For people with dementia, using one or two guideline-recommended medications appeared sufficient to protect against recurrent MI and MACE. Beta-blockers may not provide additional survival benefits over statins and RASIs.